/Engine/Source/Editor/EditorWidgets/Public/SAssetDropTarget.h
Called when we need to check if an asset type is valid for dropping and also will have a reason if it is not
typedef TBaseDelegate_TwoParams< bool, const [UObject](API\Runtime\CoreUObject\UObject\UObject) *, [FText](API\Runtime\Core\Internationalization\FText) & > FIsAssetAcceptableForDropWithReason